The invention relates to a carbonated beverage which has been packaged under pressure in a pressure-resistant closed container.
Carbonated soft drinks packaged under pressure in cans are produced and sold on a large scale. The greater part of this market consists of lemonades, such as coke, soft drinks with a fruit flavour and the like. There is also a clear interest in cooled tea, optionally slightly carbonated and/or provided with a supplementary fruit flavour and/or sweetened.
It is also known to package coffee in cans, for consumption, for instance as ice coffee. In practice, this ice coffee is optionally sweetened and is optionally slightly carbonated. The presence of carbon dioxide in the coffee is primarily intended to provide the prickly effect which carbon dioxide is known to have. It also provides a layer of foam on the coffee after it has been poured out. The structure of this layer of foam is comparable to the structure of the foam on espresso coffee.
It is also known to package non-foaming beverages, such as tea, coffee, and fruit juice in cans in the presence of nitrogen gas and carbon dioxide gas. This combination of gases is intended to provide a thin metal package with sufficient internal pressure, so that the package has sufficient strength.
The above application involves non-carbonated (non-fizzy; non-sparkling) beverages, which means that the carbon dioxide content of the liquid is not greater than 0.15% by weight.
The object of the invention is to provide an improved type of packaged coffee drink (coffee extract), which improvement relates especially to the taste, and to a lesser extent to the foaming.
Surprisingly, it has been found that the quality and especially the taste of the carbonated coffee beverage which has been packaged under pressure in a pressure-resistant container, which beverage is based on coffee extract, with the coffee beverage having been packaged in the closed container, can be improved by the presence of nitrogen in the package.
Accordingly, the invention relates to a carbonated coffee beverage which has been packaged under pressure in a pressure-resistant closed container, which beverage is based on coffee extract, the coffee beverage having been packaged in the closed container in the presence of CO.sub.2 and nitrogen.
The improvement of the taste is particularly surprising, since it was not known that the presence of nitrogen, known to be a highly inert gas, might have any influence on the taste. It has been found that the taste of the coffee becomes creamier and less sharp, while this taste at the same time becomes richer in character.
According to the invention, the beverage consists of coffee extract (coffee), optionally supplemented with conventional additions, such as sugar, sweeteners, nutrient acid and the like. It is also possible to add supplementary flavour components to the beverage, such as cinnamon, cocoa, rum flavour, fruit flavours and the like.
The coffee extracts to be used can have been obtained in a known manner by extraction of roasted coffee, and supplemented with water to the desired strength. If desired, one can also start from a wholly or partly decaffeinated coffee, or from a blend of decaffeinated and non-decaffeinated coffee.
Optionally, the beverage can also be supplemented with an amount of alcoholic beverage, such as rum, whisky, and the like. It is possible to add milk or milk products to the beverage. If desired, it is also possible to add so-called whiteners, which are not based on milk.
According to a preferred embodiment of the invention, the contents of the container consist substantially of coffee extract, water, CO.sub.2, nitrogen, optionally in combination with aromatic, flavouring and sweetening substances.
The mutual proportions of the various components of the coffee beverage can be chosen fairly broadly, the eventual composition being partly dependent on the desired taste of the coffee drink. The amount of gas in the container (carbon dioxide and nitrogen) is chosen such that the pressure in the package is minimally at the level required for the strength of the package. A conventional pressure at room temperature is between 1.01 and 7.0 bar. In case pasteurization is to take place, the maximum pressure is preferably not higher than 3.0 bar. In this connection, it is noted that in the thin cans currently used, an internal pressure is necessary to impart the desired strength to the cans.
According to the invention, such an amount of nitrogen is added that the pressure at 20.degree. C. is 0.2 to 2.0 bar higher than the pressure existing as a result of the addition of CO.sub.2 and which can vary from 0.5 to 5.0 bar.
The invention is specifically directed to foaming or effervescent (fizzy, sparkling) coffee, which means that the content of CO.sub.2 dissolved in the liquid is greater than 0.15% by weight, more particularly greater than 0.25% by weight (based on the weight of CO.sub.2 with respect to the total weight of the liquid).
In practice, it has been found that it is not easy to determine the proper dosage of nitrogen.
In a number of types of coffee extract, an (unpredictable) excessive foaming can occur. It has been found that a good and predictable foaming behaviour is obtained by adding from 0.5 to 10 ppm foam inhibiting agent, typically based on polysiloxanes, such as dimethyl siloxane.
It has additionally been found that another advantage of the invention resides in the fact that the use of nitrogen in the pressurized package gives an improvement of the structure of the foam layer. The consumer sometimes prefers that with ice coffee, after it has been poured out, a foam layer is present on the coffee. It is true that the presence of carbon dioxide in the package already gives rise to some foaming, but the amount and the structure of the foam are not satisfactory if carbon dioxide alone is used. By the co-use of nitrogen, the amount and the nature of the foam have been found to have clearly improved. In this connection, it is noted that it is known that nitrogen can effect an improvement of the foam structure in carbonated beverages.
For the purpose of packaging the beverage in the package, the conventional packaging techniques can be used, provided that it is ensured that the desired amounts of nitrogen gas and carbon dioxide gas are introduced into the package. This is preferably done immediately before the package is closed, prior to pasteurization. The addition can occur in the form of solid carbon dioxide or liquid nitrogen, but it is also possible to introduce the components into the package in gaseous form under pressure. This last can be done in the form of separate gases or by first mixing the gases in the proper amounts and dosing the mixture under pressure.